AUGUSTA (AP) — Partisan positions hardened Tuesday over the McKernan administration’s plan to allow new pollution from an industrial expansion in northern Maine by drawing upon air-quality “credits” resulting from auto-emission testing in southern Maine.

Senate President Dennis Dutremble and House Speaker Dan Gwadosky renewed their call for Gov. John R. McKernan to withdraw his plan to apply the credits to Louisiana-Pacific Corp.’s proposed waferboard mill expansion in New Limerick until lawmakers can agree on a state policy.

The two Democratic legislative leaders spoke at Tuesday’s opening meeting of a legislative panel that plans to hold hearings on the three-week-old emission testing program to assess what changes should be made.

Dutremble, D-Biddeford, asked the committee to report by September whether lawmakers should convene this fall to consider emergency action to reshape the program, and devise a short-term policy for distributing the credits Louisiana-Pacific is seeking. The same panel has until the end of the year to propose longer-term revisions for the next Legislature to consider.

“It’s a dramatic change in policy,” Gwadosky, D-Fairfield, said of the credits. “We have to do what’s right for the entire state.”

But John Devine, the Republican governor’s legal counsel, said his boss is committed to the proposal. He accused the Democratic legislative leaders of standing in the way of economic growth in northern Maine, and said McKernan refuses to “be an accomplice.”

Advocating a months-long delay to establish a state policy “amounts to saying 70 jobs aren’t important to northern Maine,” Devine said, adding that the company wants firm direction from the state by September.

Gwadosky dismissed Devine’s remarks as “overly simplistic” and said, “We don’t think that this giveaway (of credits) is fair.”

Louisiana-Pacific fanned the flames this week. In a letter to the chairmen of the legislative panel, the company’s development manager warned that legislative delays may force the expansion to be built outside of Maine.

“If it will cost more or take longer to build in Maine, which appears to be where we are heading, I cannot recommend that we expand here. … Our expansion now appears to be up to the Legislature,” Peter D. Chase wrote.

The credits in question represent reductions in nitrogen oxides that are greater than what the federal Clean Air Act requires through the auto testing program launched July 1 in seven southern Maine counties.

The law requires a reduction of 800 tons per year of those emissions. The testing program is expected to reduce the emissions by 2,000 tons, leaving credits of 1,200 tons. The administration proposes using a portion of those credits to offset pollution from the new Louisiana-Pacific facility.

The credits would not become available until the federal Environmental Protection Agency approves Maine’s emission testing program, although a decision is required by Sept. 15 and Devine said the administration is “very confident” that the program will pass muster.

At the same time, the administration has asked the EPA to exempt northern Maine from the Clean Air Act altogether, said acting state Environmental Protection Commissioner Debrah Richard.

If the state can convince the EPA that more smokestack controls would not significantly improve northern Maine’s air quality, and the exemption is granted, Louisiana-Pacific would not need the emission credits, she said.